A combination of inadequately trained pilots and equipment failure caused Air France Flight 447 to plunge into the Atlantic Ocean in 2009, killing all 228 people on board, French investigators said in their final crash report on Thursday.

The June 1 flight from Rio de Janeiro to Paris disappeared during a thunderstorm.

After the plane stalled, the crew—which lacked proper training for a "surprise" scenario—"was in a state of near-total loss of control," the report from France's Bureau of Investigation and Analysis said.

The pilots of the Airbus A330 "likely never realized" the plane had stalled, chief investigator Alain Bouillard said. Due to invalid sensor readings, they thought the plane was in a dive, and pulled the nose up.

"A basic maneuver for stall recovery, which pilots are taught at the outset of their flight training, is to push the yoke forward and apply full throttle to lower the nose of the plane and build up speed," the Associated Press explained. "But because the pilot thought the plane was diving, he nosed up."

The Air France Flight 447 crash was France's deadliest ever.

According to CNN, it took "four searches over the course of nearly two years to locate the bulk of the wreckage and the majority of the bodies in a mountain range deep under the ocean." The voice recorder and flight data recorder were found in May 2011.

"The report describes a crew who acted in line with the information provided by the cockpit instruments and systems, and the aircraft behavior as it was perceptible in the cockpit," Air France said in a statement Thursday. "The reading of the various data did not enable them to apply the appropriate action."

A separate French judicial investigation is still under way, the AP said, with Air France and Airbus facing preliminary manslaughter charges.